Thanks Dan,
His wife just called me back. As I head out on the road in a week, time was getting tight. Glad to hear Kirk is a good guy. I told them i was part of the Wetpixel crew and that we were building a fan club for them:)
I'll let you know how it works out.
shawn

Talked with L&M. You want the 72mm acrylic cc filter (blue water), not glass. Apparently the glass delivers inconsistent results. Also, first check sounds like the Expodisc may not work when using the UWA lens (not enough space between cameral and UWA lens...very tight). This is unconfirmed hear-say...so don't quote me. L&M is really backing us on getting the Expodisc to work with all lenses. Dan has been doing a famous job on leading the charge and Eric has been great in bring it to the masses.
Thanks Dan and Eric or introducing this innovative technique.

Finally, I want to take back when I said URPRO is unresposive. Kirk has been traveling and this is a small operation. Since, they have been incredibly customer focused!

I can confirm that the glass filter does not work, I tried it two weeks ago and thought I may have received the shallow water version by mistake. It would only white balance in very shallow water. I spoke to URPro about it and think I mentioned it to L&M, don't remember. I now have the plastic one, but it won't help me right now because the current 6mm Expodisc will definitely not fit between the camera and Bluefin HD UWA lens. I do know there are multiple people who are putting their minds together to come up with a specialized Expodisc that will fit in the Bluefin HD housing, but I can't tell you who.
Dan

How are you guys who bought 72mm UR-Pro discs (ShawnH, Eric etc.) holding them recessed in the front of the camera? Would it be feasible to use just the threaded part of a filter ring to retain the plastic disc and machine the protruding part of the ring off so it's flush or sub-flush?

Or would I be better off with Wagsy's method of pushing a whole 67mm filter and ring into the front of the camera with a bit of tape for padding?

Hey, Nick. Unscrew the inner retaining ring from the filter and then put the filter element into the camera's threaded lens area. Screw the retaining ring nside the camera's threaded lens area to hold the filter in.